Ultrasound enhancement of dissolution kinetics of uranium oxides in supercritical carbon dioxide

Abstract

The enhanced dissolution of uranium oxides by the application of ultrasound in supercritical uid carbon dioxide containing dissolved 4,4-tri¯uoro-1-(2-thienyl)-1,3-butanedione and tributyl phosphate is demonstrated. Under conditions of 60°C and 150 atm the steady state dissolution of UO 3 with soni®cation is increased by approximately 100%. Furthermore, the effect of adding hydrogen peroxide to the supercritical system above enables the lower oxides of uranium, UO 2 and U 3 O 8 , to be extracted.

Optimizations and comparison of two supercritical extractions of adlay oil

“…Trofimov used ultrasound during the dissolution of uranium oxides in supercritical carbon dioxide. The results showed the dissolution of uranium trioxide with sonification was increased by approximately 100% at 60°C and 150 atm (Trofimov, Samsonov, Lee, Smart, & Wai, 2001). More recently the use of power ultrasound in SFE to enhance the extraction yield of oil from almonds was reported by Riera, Golas, Blanco, Gallego, Blasco, & Mulet (2004), and he found that power ultrasound significantly accelerated the kinetics of the process and improved the final extraction yields by 20%, due to the effects produced by ultrasound, such as the compression, the decompression, radiation pressure and acoustic streaming.…”

Characterization and remediation of soils contaminated with uranium

“…There are numerous published papers which highlight the use of supercritical fluids for uranium extraction [226,229,[231][232][233][234][235]. Direct dissolution of recalcitrant uranium oxides using nitric acid and metal-complexing agents in supercritical fluid carbon dioxide has also been reported [236][237][238].…”

“…Primordial uranium consists of three isotopes, 238 U and 234 U from the uranium series and 235 U from the actinium series. In nature, an imbalance between 234 U and 238 U may exist due to alpha particle withdraw from the decay of 238 U that increases the availability of 234 U for transport through geological processes.…”

Ultrasound-Enhanced Dissolution of UO2in Supercritical CO2Containing a CO2-Philic Complexant of Tri-n-butylphosphate and Nitric Acid

“…One technical problem that needs to be solved is enhancement of the UO 2 dissolution rate, which is necessary for effective reprocessing in real applications because of the narrow space available in the spent fuels. Ultrasound has been shown to promote the conversion of nitric acid to nitrous acid , and to aid in the removal of solutes from solid matrixes …”